Sauté finely chopped Spanish onion in olive oil for 1-3 minutes until soft and translucent

Add crushed garlic and tomato paste, sauté for about 30 seconds until fragrant

Add dried oregano and toast for a couple seconds

Add one 28 ounce can of whole peeled San Marzano tomatoes and mash with a potato masher

Bring to a simmer, lower heat, and cook for 45 minutes to 1 hour, adding minimal water

Add fresh basil sprig and cook until sauce is mellow and sweet

For fresh pasta: pile 550 grams flour into a volcano shape, add 5 eggs and 2 teaspoons salt

Beat eggs with a fork, slowly adding flour while maintaining the flour walls

Switch to hands or bench scraper and knead until homogeneous

Wrap dough in plastic and rest for 30 minutes

Knead by hand or pass through pasta roller on widest setting, folding into thirds and repeating 1-3 times

Roll dough out to ⅛ inch thick and trim into lasagna sheet-sized pieces

Dust sheets with flour, stack, and keep under a moist kitchen towel

For béchamel: bring 8 tablespoons butter to a bare simmer

Add 63 grams flour and whisk into a paste (roux), cooking for 1-2 minutes until nutty smelling

Add 4.5 cups cold milk slowly, one splash at a time, whisking until fully incorporated

Bring to a simmer, reduce heat, and cook for 3-5 minutes until thick and glossy

Season with ¾ teaspoon kosher salt, ½ teaspoon white pepper, and ¼ to ½ teaspoon nutmeg

Cover béchamel directly with plastic wrap and cool for 30 minutes

Grate 1 pound of low moisture mozzarella and Parmesan cheese

Optional: brown 1 pound Italian sausage and add to sauce

Spread a bit of sauce on the bottom of the pan

Layer pasta sheets, sauce, mozzarella, Parmesan, and béchamel, repeating until full

Make top layer light on sauce and heavy on cheese

Cover with foil and bake at 375°F for 30-45 minutes until cheese is melted and edges bubble

Remove foil and bake uncovered for 15-20 minutes until nicely browned

Pop any large bubbles with a cocktail pick

Let rest for at least 30 minutes before serving

Garnish with extra béchamel, tomato sauce, basil, or nutmeg